MiR-659-3p inhibits osteosarcoma progression and metastasis by inhibiting cell proliferation and invasion via targeting SRPK1.

Objective: Osteosarcoma is the most common primary bone cancer that affects mostly children and young adults. Despite the advances in osteosarcoma treatment, the long-term survival rate of metastatic patients has not significantly improved in the past few decades, thus demonstrating the need for novel therapeutic targets or methods to improve metastatic osteosarcoma treatment. In this study we aimed to elucidate the role of miR-659-3p and SRPK1 in osteosarcoma.

Methods: We evaluated miR-659-3p and SRPK1 function in osteosarcoma cell proliferation, migration, and cell cycle progression in vitro by using gain- and loss-of-function strategies. The effect of miR-659-3p in tumor progression and metastasis was determined by in vivo mouse model.

Results: We revealed that expression of miR-659-3p was significantly downregulated in osteosarcoma compared with normal bone cells and was inversely correlated with serine-arginine protein kinase 1 (SRPK1) expression. We proved that miR-659-3p targets 3' UTR of SRPK1 and negatively regulates SRPK1 expression in osteosarcoma cells via luciferase assay. In vitro studies revealed that gain of miR-659-3p function inhibited osteosarcoma cells growth, migration, and invasion by down-regulating SRPK1 expression. Inversely, inhibiting miR-659-3p in osteosarcoma cells promoted cell growth, migration, and invasion. Cell cycle profile analysis revealed that miR-659-3p inhibited osteosarcoma cells' G1/G0 phase exit by down-regulating SRPK1 expression. By using an in vivo mouse model, we demonstrated that miR-659-3p inhibits osteosarcoma tumor progression and lung metastasis by inhibiting SRPK1 expression and potentially downstream cell proliferation, and epithelial-to-mesenchymal transition genes.

Conclusions: This study demonstrated that miR-659-3p is a potential therapeutic method and SRPK1 is a potential therapeutic target for osteosarcoma treatment.